Elevator door control



June 17, 1969 A. M. HALLENE ET AL 3,450,232

' ELEVATOR DOOR CONTROL Filed Aug. 18, 1967 Sheet or 9 FIGI n. I I QP HATCHWAY DOOR INVENTORS. ALAN M. HALLENE HENRY J. HOLUBA JOHN J. DREXLER ATTORNEYS- June 17,, 1969 5' Ora Sheet Filed Aug. 18. 1967 Fuss/x m ETm M is N L June 17, 1969- A; M. HALLEN E ET AL 3,450,232

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DROP OUT RELAY June 17, 1969 A. M. HALLENE E AL I ,232

ELEVATOR DOOR CONTROL Sheet Filed Aug. 18, 1967 FIGGA |l.l|ll| |lll||l|l|l| l IIVIIIIIIIIII lllllll2nllil3 ll aiiiiiiliii.ii}-iilfiililiilllI|| June 17, 1969 ELEVATOR DOOR CONTROL Sheet Filed Aug. 18, 1967 FIG. 7A

United States Patent US. Cl. 187-61 5 Claims ABSTRACT OF THE DISCLOSURE An elevator control continuously moves a car door through an opening and closing operation, without pausing at a full open position, and moves the car door at substantially different speeds to control the total door open time. The breaking of a photobeam across the doorway modifies the speed and direction of movement of the door. When the door photobeam circuit becomes inoperative, the speed of operation of the car door is modified until the condition is remedied. Should a door lock fail to unlatch, opening direction power is discontinued and closing direction power is applied to the car door motor to reestablish electrical interlock contacts in the hoistway.

BACKGROUND OF THE INVENTION This invention relates to an elevator control, and more particularly to a control for an automatic elevator car door.

Prior elevator door controls have met with limited success when operating under certain adverse conditions, such as heavy traffic demands in an under-elevatored installation, or inoperative control circuits which cause door operation to be partially or totally disabled until repairs can be undertaken.

For example, typical automatic elevator controls shorten the door open time of a fully open door when a photo beam is broken, to expedite car departure after load transfer. Such an installation does not take into account the basic problem involved in an under-elevatored installation, namely, an oversupply of passengers transferring at too slow a speed for the amount of traffic to be handled. The control fails to solve the problem because it merely operates the car door in conformity with the tratfic flow which has already occurred, rather than attempting to provide some measure of control over the traffic flow itself.

Another adverse condition which at least partly disables an elevator control occurs when a photoelectric door circuit becomes inoperative, as by a light bulb becoming burned out. Prior elevator controls have continued to operate the door, as by cutting out all safety devices after the expiration of a long failure time period, but each door operation thereafter, until the circuit is repaired, is subject to the same disability, and passengers must wait for the expiration of the long failure time or the like at each floor before the elevator door will close. Such a control is intended only as a safety override, when smoke or the like blocks a photobeam, and is unsatisfactory to compensate adequately for circuit failures, some of which may not be of sufiicient importance to warrant immediate repair.

A different type of disability occurs when a mechanical interlock for a hoistway door fails to unlatch at a floor. As opening direction power is applied through the car door to the hoistway door, electrical interlock contacts (generally in the hoistway) may become disengaged, even though the mechanical interlock has failed to open. In prior installations, such an occurrence renders the elevator system completely inoperative, since the elevator car is incapable of opening its door, and is unable totravel through the hoistway to other floors.

SUMMARY OF THE INVENTION The elevator door control disclosed herein overcomes disadvantages of previous controls by providing a measure of control over the traffic flow, both during normal 'operating conditions, and during abnormal conditions caused by mechanical, electrical or other failures. To expedite passenger movement, the door is continuously moved through an opening and closing operation, without pausing at its fully open position. It has been found that such operation urges passengers to transfer more rapidly. The total door open time is controlled by operating the door at a very slow or creep speed for a major portion of the time the elevator passageway is open to load transfer. Preferably, the creep speed operation occurs during the final opening movement of the door, since passengers are less hesitant to pass through the passageway while the door is opening away from them. I

A load sensing device, as a photoelectric circuit, modifies the door operation upon load transfer. According to one embodiment, when the car is not stopping for a hall call, and a passenger breaks a photobeam, the door immediately reverses its direction of movement and closes at creep speed until a short time after the beam is restored, when full closing speed occurs. Alternately, in another embodiment, when the car does not stop for a hall call and a passenger breaks the photobeam, the door does not immediately reverse direction on a photobeam break, but rather continues to open at a fast speed, bypassing the door open creep speed. In some circumstances, such as when the car stops for a hall call, a greater amount of time should be provided for load transfer. In such a case, the door operates at creep speed during the final opening movement, regardless of whether or not the beam is broken while the door opens. It has been found that the above described operation materially increases the speed rapidity with which passengers trnasfer between a landing and an elevator car. Many passengers tend to transfer rapidly while an elevator door is moving, as contrasted with relatively slower passenger movement when an elevator door remains at rest in a fully opened position.

Should the photoelectric circuit become disabled, as when the light bulb becomes burned out or dirt obstructs the photobeam, the door operation is modified to allow the doors to close within a reasonably short time interval. As the elevator car moves through the hoistway, a testing circuit determines whether the blocked photobeam at the previous landing was caused by normal passenger transfer, or by an abnormal condition, such as a circuit failure. If the blocked photobeam was caused by a circuit failure, the door operation is modified by opening the door fully at the conventional, or fast speed, and thereafter immediately closing the door at an intermediate speed.

Should a mechanical door interlock fail to unlatch when an elevator car is to open its door, the door opening mo- I tor may produce a slight movement of the car door sufficient to open the electrical interlock contacts in the hoistway. The elevator system operation is maintained by discontinuing opening direction power and applying closing direction power to the door, causing the electrical interlock contacts to close. The elevator car will now continue service in a normal manner.

One object of this invention is the provision of an improved control for an elevator door.

Another object of this invention is the provision of an elevator door control which modifies the opening and closing operation of the door to overcome adverse operating conditions.

One feature of this invention is the provision of an elevator door control which continuously moves a door through an opening and closing operation. The speed of movement, preferably while the door is opening, controls the door open time.

Another feature of this invention is the provision of an elevator door control which modifies the door operation if a passenger enters or leaves during opening movement of a door by either stopping the door and immediately starting to close the door, or by causing the door to open fully at fast speed, bypassing the slower speed operation during the final opening movement of the door.

Yet another feature of this invention is the provision of an elevator door control which tests the operation of a load transfer detection circuit. If a failure has occurred, the control modifies the door operation to provide service without the functioning of a load detection circuit.

Still another feature of this invenion is the provision of an elevator door control which recognizes when a mechanical door interlock fails to unlatch, and modifies the door operation, allowing the elevator system to continue to service the other floor.

Further features and advantages of the invention will be apparent from the following description and from the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an elevator car suitable for use with the door control of this invention;

FIG. 2 is a fragmentary plan view, taken along line 22 of FIG. 1;

FIG. 3 is a block diagram of the electrical control circuit for the elevator car door;

FIG. 4 is a series of diagrams of elevator door speed versus elapsed time, for opening movement of the door (solid lines) and for closing movement of the door (dashed lines), under different operating conditions, in which:

FIG. 4A shows door operation when the photobeam is not broken,

FIG. 4B shows door operation when the photobeam is broken during the fast speed opening of the door,

FIG. 4C shows door operation when the photobeam is broken during slow speed opening of the door,

FIG. 4D shows door operation when the photobeam is broken during fast speed closing of the door, and

FIG. 4E shows door operation when no photobeam is present (inoperative photoelectric circuit);

FIGS. 5-7 are continuous across-the-line circuit diagrams for an elevator door control circuit embodying the invention; and

FIGS. 5A-7A are key diagrams of the components in FIGS. 5-7, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENT General operation In FIGS. 1 and 2, an elevator system is illustrated which is suitable for use with applicants invention. An elevator car is guided by hoistway rails 21 extending vertically along the sides of a hoistway for a single one or a bank of elevator cars. Car 20 is supported by a cable 22 con nected to drive equipment (not illustrated).

The elevator car is positioned at a floor or landing 25, where load transfer occurs through a passageway or doorway between the landing and the elevator car. A car door 26 is moved through an opening and closing operation to expose and block the passageway to load transfer. While only a single door is illustrated, the invention is equally applicable to cars having double doors, each door being formed from one or more sections.

The passageway is also blocked to load transfer by a hoistway door 28 located at each landing 25. Car door 26 carries interconnecting apparatus 30 which latches with the hoistway door adjacent thereto to open the hoistway door as the car door is driven open. A hook 31, mounted on each hoistway door, mechanically engages a corresponding latch 32 located in the hoistway, to prevent the hoistway doors from opening unless the elevator car is adjacent that landing. When the elevator car door is to open, a conventional unlatch mechanism (not illustrated) becomes actuated to disconnect hook 31 from latch 32. Each latch 32 includes electrical interlock contacts which close when hook 31 connects with the latch. The contacts are connected in an elevator control circuit to prevent the car from running through the hoistway unless all the hoistway doors are closed.

A sensing device, mounted on car 20, determines when a passenger or other load is present in the passageway. Such a sensing device may comprise a light source 35 which projects a photobeam 36 across the passageway to a photoelectric cell 37. Photobeam 36 is positioned to be broken when a load is moved into the doorway.

The circuit illustrated in block form in FIG. 3 controls the operation of the elevator system of FIGS. 1 and 2. A suitable elevator control 40 initiates the starting, running and leveling operations of the elevator car. Control 40 includes a circuit 42 which registers hall calls from stations 43, FIG. 1, and car calls from station 44, FIG. 2. A starting circuit 26 is responsive to one or more registered calls to cause the car to move through the hoistway in the proper direction. As the elevator car ap proaches a landing for which a call in the proper direction is registered, a decelerating circuit 48 slows the movement of the car, while a leveling circuit 50 levels the car to the landing.

The door is now opened and closed by elevator door control 60. A variable speed door motor 61 is initially under control of a door open time and speed control circuit 63. A photoelectric circuit (PEC) 64, which includes light source 35 and photoelectric cell 37 of FIG. 2, is responsive to the breaking of photobeam 36 to modify the movement of the door. Should PFC 64 become inoperative, as by light source 35 becomin burned out, or by smoke obscuring the photobeam, 'PEC override circuit 66 effectively disconnects PEC 64 and controls the operation of door motor 61 in a modified manner. When normal PEC operation is restored, override circuit 66 is automatically disconnected from further control over the operation of the door.

Door control 60 also actuates the previously described mechanical hoistway door unlatch mechanism (not illustrated) when the car door is to open. Should the hook 31 fail to unlatch, a mechanical failure override circuit 68 overrides the operation of door open time and speed control circuit 63 and modifies the normal opening operation of the door.

In the discussion of the circuit, the following letter designations will be used:

Symbol: Relay C Door Motor Closing Power.

DCL Door Close Limit.

DE Door Operator Pilot.

DO Door Open Signal.

DOL Door Open Limit.

DOX Door Fully Open Signal.

DS Car Call Button Operation.

DT Door Reverse Signal.

.EE Photoelectric Beam Signal.

EEX Slow Door Closing Signal.

EEY Photoelectric Failure Sensing.

EEZ Photoelectric Failure Memory and Medium Door Close Speed.

HC Hall Call.

LRA Leveling Zone Indication.

O Door Motor Opening Power.

OX Door Open Slow.

RA Motion Indication.

S Starting Signal.

'5 Symbol: Relay SAF Stop Switch Indication.

SDR Door Motor Slowdown.

TD Latch Timing Interval.

TDA Door Timing Expires.

TDAT Door Release Timing.

TDCL Delayed Door Close Limit Signal.

UDC Car and Hall Cal-l Pick-up Signal.

SWITCH SWla and SWlb Mode Transfer (ganged switches).

Relay contacts are identified by the letter designation of the relay followed by the number designation of the contact, as shown in the key, FIGS. A-7A.

Door open time and speed control The operation of door open time and speed control circuit 63, FIG. 3, will be described with reference to the diagrams of FIGS. 4A-D. When the elevator car answers either a car or hall call, and the photobeam is not broken, FIG. 4A, the door initially opens, as shown in solid lines, at a fast speed suflicient to expose the passageway to load transfer. As the door reaches a predetermined position located a short distance before the fully open position, as six inches, its speed is reduced to a very slow or creep open speed.

The creep speed continues for a major portion of the total time necessary for the car door to open fully. Upon reaching full open, the door is quickly braked, and thereafter instantly starts to close at a fast closing speed, as shown in dashed lines, which is slightly less than the fast opening speed. It should be noted that the car door does not stop at its fully open position. Thus, the total door open time, that is, the total time that the door is away from its fully closed position, does not include a period in which the door stands fully open, but rather is determined by the speed of movement of the door. The creep speed, it should be further noted, is not the speed necessary for any moving body to slowdown to reverse direction, due to the inertia of the body. As can be seen from the drawing, the creep speed is in addition to, and is substantially larger than the brake speed in which the door decelerates from its opening velocity in the immediate vicinity of the fully open position to zero velocity, and thereafter accelerates in the opposite direction to its closing speed.

When the photobeam is broken, the cycle of movement for the door, as illustrated in FIGS. 4B-D, depends upon whether a car call or a hall call is being answered. In addition, when answering a car call, one of two dilferent methods of door operation, determined by the setting of a mode switch SW1, FIGS. 67, effectively shortens the door open time upon a photobeam break. Briefly, when the mode switch is in its A position or mode, and a car call is being answered, the door starts closing upon the earliest interruption of the photobeam after the door begins to open. When the switch is in the B position or mode, and a car call is being answered, the door, which must open fully, entirely bypasses the creep speed operation, or the portion of it still remaining after the photobeam is broken, thus moving the door through the remaining distance at its fast speed.

When answering a hall call, regardless of the position of the mode switch, the door always initially opens at its fast speed, and after passing the predetermined position previously defined, operates at creep speed until fully open. Thus, independent of the mode, the relatively short total door open time efiective when answering a car call is lengthened when answering a hall call.

The choice between the A or B mode of operation will depend upon the amount of traflic to be handled and the particular installation at which the control is used. The A mode, in which the door immediately closes upon a beam break, is suited for urging passengers to transfer more quickly, while discouraging later arriving passengers from attempting to enter the car. The B mode, in which the car door continues to open after the first beam break, may be desired where lighter trafiic flow is encountered, since passengers waiting in the hallway are less reluctant to enter a car while the door is opening, and hence will transfer at a later time in the elevator door cycle.

The operation of the door will now be described in more detail, with reference to FIGS. 4B-D. In FIG. 4B, the photobeam is initially broken at a point Y, while the door is moving at a fast opening speed. If the elevator car is operating in the A mode while responding to .a car call, the door immediately reverses direction upon the photobeam being broken, and closes at creep speed. The door continues to close at creep speed for a short time period (as two seconds) after the photobeam is restored, and thereafter transfers to a fast closing speed. The delay in initiating fast closing permits several passengers to move through the doorway in close succession.

If, however, the elevator circuit is operating in the B mode while responding to a car call, the door opens fully at fast speed, bypassing the creep speed operation, and immediately reverses direction upon reaching the fully open position. Assuming the photobeam has been restored prior to the door reaching its fully open position, the door will close in the same manner :as though there was no beam break.

When the car has stopped at a landing in response to the registration of a hall call, either alone or with a car call also being registered, the control (regardless of whether in the A or B mode) operates to lengthen the door open time. Even though the photobeam may be broken during opening movement, as in FIG. 4B, the door continues to operate as though no beam break had occurred. That is, the door continues to open at fast speed until reaching the predetermined position, and then opens at creep speed until fully open. Upon reaching the fully open position Z, the door immediately reverses direction and closes at fast closing speed.

The operation of the door will now be explained for a beam break first occurring during door opening at creep speed, as seen in FIG. 4C. If the car has stopped in response to a car call, and is operating in the A mode, the door immediately reverses direction and closes :at a creep speed until a short time period after the beam is restored, and then closes the remaining distance at [full speed. If the car is operating in the B mode and has stopped for a car call, the creep speed operation is bypassed, and the door immediately resumes full opening speed upon beam break. If the car has stopped for a hall call, the door continues to operate at creep speed during its final opening movement, regardless of a beam break. Whether operating in the B mode or in response to a hall call, if the beam is still broken when the door reaches its fully open position Z, the door will immediately reverse direction and close at creep speed, continuing at creep speed ifOl' a short time period after the beam is restored. Upon the lapse of the short time period, the door will close at its full closing speed.

In FIG. 4D, the operation of the door is illustrated 'When the beam is first broken during the closing operation. For both car and ball calls, the door slows to creep closing speed upon the occurrence of a beam break, and continues closing at creep speed until the expiration of a short time period after the beam is restored when fast closing speed resumes. Should the beam again be broken prior to the doors reaching their fully closed position X, the door would again slow to creep speed.

Safety controls of a conventional nature complement the door operation outlined above. If at any time while the doors are closing, either at creep or fast closing speed, the door open button or the car call button corresponding to the floor at which the elevator is standing is pressed, or contact is made with the door safety edge, the door instantly reverses its direction and opens. Upon reaching the full open position, the door immediately starts to reclose, as previously described, if none of the door reopening devices is then being operated.

Similarly, pressing a hall call "button corresponding to the set direction of travel of the car standing at .a landing, while the door is closing, causes the door to reverse its direction of travel and open. Immediately upon reaching its open position, the door recloses in the manner previously described. The door will remain open only if the open button, the safety door edge contact, or the stop switch is actuated.

It should be noted that the door control does not provide any fixed amount of door open time, but rather operates in response to passenger action to expedite elevator movement. For example, in FIG. 4B, the door open time, i.e., the total amount of time the door is away from its fully closed position, is considerably less than the door open time in FIG. 4A, when the photobeam is not broken. Conversely, in FIG. 4D, the door open time is considerably greater than either of the above door open times.

The operation of door open time and speed control circuit 63 may be briefly summarized as tfollows. As the door opens at a landing, it actuates a cam operated EARLY OPEN SLOWDOWN switch, FIG. 5, mounted on the door operator, to establish when the door is Within :the last six inches of door movement towards the full open posit-ion. As a result, relay OX picks up, closing contact OX-l and inserting resistor R-S in series with resistor R-4 across the motor armature, reducing the door opening speed to a very slow or creep speed. As the door reaches its full open position, :an OPEN LIMlT switch opens deenergizing relay DOL. Contact DOL1, FIG. 6, which is in series with the door open relay DO, returns to its normally open position, causing relay D to immediately drop out as the doors reach the fully open position, thereby initiating a closing operation. Thus, the door moves continuously through an opening and closing operation, without a pause.

Disabled photoelectric circuit override The operation of disabled PEC override circuit 66 will be explained with reference [to the door speed versus time diagram in FIG. 4E. The door operation is modified when a PEC failure occurs, such as a burned out light source lamp 35, or dirt or smoke throughout the hatch-way 'being responsible for the degradation of the photoelectric beam 36. If the photoelectric circuit 64 first became inopenative while the door was moving across the passageway, the door would, at that landing, move to its fully closed position in the same manner as though the photo beam became blocked by load transfer.

As the elevator car travels through the hoistway, a testing circuit is responsive if the photoelectric cell has no output at this time, to record a failure of PEC unit 64, since nothing should be blocking the photobeam while the car travels through the hoistway. The recorded failure modifies the next operation of the door control, causing the door to open fully at its conventional, i.e., fast speed, whereupon reaching the full open position, the door immediately begins to close at an intermediate closing speed, between the fast closing speed and the creep closing speed. Such modified door operation, which occurs whether the car is stopped for a car or hall call, provides continuity of elevator service by providing optimum fixed door operation when the door control circuit cannot recognize load transfer.

All devices effecting door reopening, that is, the door open button, car call buttons, door safety edge contact, sto switch, and hall call button corresponding to the direction of travel of the car at the floor where it is standing, operate in a normal manner as when the photoelectric circuit is operative. Upon correction of the failure in the photoelectric circuit, normal door operation is automatically restored.

The operation of disabled PEC override circuit 66 may be briefly summarized as follows. When photobeam 36 is broken, relay EE, FIG. 5, becomes energized. Contact EE-2, FIG. 6, closes to pick up relay EEX. As the elevator car begins to move through the hoistway, relays EEY and EEZ, FIG. 7, are picked up providing the beam remains broken at this time. Relay EEZ becomes self-holding as the elevator car initiates its slowdown for the next stopping floor, setting up a memory function indicating a failure of the photoelectric circuit.

The elevator car opens its door fully at conventional speed. When the door reaches its fully open position, relay DOL drops out, opening contact DOL-2 which causes relay-EEY to drop out.

The door now begins to close, as when the photobeam is blocked, except that relay contact EEZ-1, now open, disconnects resistor R-4 from the armature. As a result, the door closes at a medium speed, between the slow closing speed (when resistor R-4 is inserted across the armature) and fast closing speed.

The brake is released as the elevator again travels through the hoistway, dropping out relay EEZ. Relay EEY now re-evaluates the PEC failure. If the photoelectric circuit is still inoperative, relay EEY again becomes energized to initiate another modified elevator door operation, by setting up a memory function in relay EEZ. However, if the failure condition has been rectified, as by replacing a burned out light source, or because the elevator car has travelled past smoke which has obscured the photobeam, relay EEY is not picked up, and thus normal operating conditions are re-established.

Mechanical failure override The operation of mechanical failure override circuit 68 will be explained with reference to the elevator structure of FIGS. 1 and 2. Sometimes when door opening motion is applied to fully closed elevator car door 26 and hoistway door 28, the unlatching mechanism for the hook 31 may not succeed in unlatching the hoistway door. However, a slight door movement may occur, sufiicient to open the electrical interlock contacts. The latched book 31 stalls the elevator car doors, while the open electrical contacts prevent the elevator from travelling to a different landing.

Override circuit 68 prevents the interruption of elevator service which would otherwise occur with the type of failure discussed above. If the doors do not open when opening direction power, has been applied to them, an override signal is generated which modifies the operation of the door control. Opening direction power is disconnected and closing direction power is applied to the doors, to re-establish the electrical interlock contacts 32 and allow the elevator car to service other floors.

The operation of mechanical failure override circuit 68 may be briefly summarized as follows. When the door is to open, contact DO5, FIG. 7, closes to energize a delayed latch timer TD. Contact DCL-4, in series with timer TD, opens when the CLOSE LIMIT switch is released. If the CLOSE LIMIT switch remains actuated, indicating the door is latched shut, timer contact TD1 closes after a time delay sufiicient for the door to have begun opening, to produce an override signal which drops out the door open relay DO, initiating a closing sequence.

Detailed description Referring to FIGS. 5-7, a source of DC voltage (not illustrated) is connected across power lines and The supply for the elevator apparatus other than the DC door motor 61 could, however, be supplied from an AC voltage source, if desired.

The door operating mechanism utilizes a shunt wound DC motor 61, FIG. 5, the field of which is directly connected across the and power lines. The armature of motor 61 receives bi-directional power for opening and closing the mechanically interconnected hoistway and car doors, at different speeds, through various and C relay contacts, and resistors R1, R2, R3, R4 and RS. The door operating mechanism shown in FIGS. 1 and 2 provides for the cam operation of limit switches CLOSE LIMIT, OPEN LIMIT, CLOSE SLOW- DOWN, OPEN SLOWDOWN and EARLY OPEN SLOWDOWN, in accordance with the position of the door.

The circuits in control 40 operate to close momentarily the CAR AND HALL CALL PICKUP contact, FIG. 6, to energize relay UDC whenever the car is conditioned to stop at a floor for a car or hall call. These same circuits operate to close momentarily the CAR AND HALL CALL PICKUP contact to energize relay UDC whenever an appropriate car or hall call button is pressed to cause the closing doors to re-open. Call registering circuit 42 operates to energize hall call relay HC when a hall call at the floor to which the elevator car is stopping has been registered, whether or not a car call has also been registered.

Starting circuit 46 operates to energize relay S, FIG. 7, when the car is conditioned to close its doors in anticipation of providing further service. Relay S remains picked up thereafter (unless the doors are caused to re-open) until the elevator initiates its slowdown after running to the next floor to be served, or, in the event that the car is to remain at rest at a floor, until the doors have fully closed and no direction preference remains assigned to the elevator.

The sequence of operation is as follows for a car call. As the car is running through the hoistway, the CAR AND HALL PICKUP contact, FIG. 6, momentarily closes shortly before the car begins to slowdown for the car call. HALL CALL relay HC is de-energized at this time. When the CAR AND HALL CALL PICKUP contact closes, UDC momentarily picks up. UDC-1 closes to pick up DO through TDA-1 and DOL-l. DO seals in through TDA-1, DOL1 and DO2.

A contact on the elevator brake closes to energize relay RA when the brake is released (car in motion), and opens when the brake is set (car stopped). Leveling unit switches on the car closes to energize relay LRA when the elevator is within the door opening zone of a floor where it is stopping or stopped.

As the car levels with the floor at which it has been conditioned to stop, it enters a door operating zone in which the car leveling unit switches, FIG. 6, close to pick up LRA. LRA-Z closes to pick up DE thru DO-3. DE-2 closes to pick up 0, FIG. 5, through OPEN LIMIT switch, which opens only when the door is fully open. O-1 and 0-2 close, O3 opens, and opening direction power is applied to the door motor through R-l, O-2, SDR2, armature, and O-l. The mechanically latched hoistway and car doors begin to open at normal speed.

As soon as the doors have moved away from the fully closed position, CLOSE LIMIT switch, which opens only when the door is fully closed, closes to pick up DCL and TDCL. As the doors reach a position six inches from full open, the EARLY OPEN SLOWDOWN switch, which closes only while the doors are within six inches of their fully open position, closes to pick up OX through DT-3 and O-7. OX-l closes to connect the series combination of R4 and R-S across the armature, causing the doors to slowdown.

As the doors approach the full open position, the OPEN SLOWDOWN switch, which closes as the opening doors near the fully open position, and remains actuated until the door subsequently closes beyond this slowdown point, closes to pick up SDR through O-S. SDR-1 closes to parallel resistor R2 across the armature, and SDR2 opens to insert resistor R3 in series with the armature to reduce the applied armature voltage so that the doors 10 further slowdown. When the doors reach the fully open position, OPEN LIMIT opens to drop-out O and DOL. O-1 and O-Z open to remove opening power from the armature. O-3 closes to place a dynamic braking short circuit across the armature through C-4, and the doors stop at their fully open position.

As the doors reach the full open position, DOL1 opens to drop-out D0, in turn opening DO3 to dropout DE. DE-l closes to pick up C through CLOSE LIMIT. C-1 and C2 close, C-4 opens, and closing direction power is applied to the door motor through Rl, C1, armature, SDR-2 and C-2. C3 closes to parallel resistor R2 across the armature. The doors start to close at normal closing speed. As soon as the doors have moved away from the fully open position, OPEN LIMIT closes to pick up DOL. When the doors have moved six inches away from the fully open position, the EARLY OPEN SLOWDOWN switch opens without effect. As the doors approach the full closed position, the CLOSE SLOW- DOWN switch, which closes as the closing door nears the fully closed position, and remains closed until subsequently opened beyond this slowdown point, closes to pick up SDR through CLOSE LIMIT and O-4. SDR-2 opens to insert resistor R-3 in series with the armature, reducing the applied armature voltage so that the doors slowdown.

When the doors reach the full closed position, CLOSE LIMIT opens to drop-out C and DCL and to remove power from TDCL (which is delayed in dropping-out). C-1 and C-2 open to remove closing power from the armature, C-3 opens to disconnect resistor R2 from across the armature, and C4 closes to place the dynamic braking short circuit across the armature through O3. The doors stop at their fully closed position and the hoistway interlock contact 32, FIG. 2, is established as the hoistway door becomes mechanically locked by hook 31. Shortly thereafter TDCL drops-out.

The photoelectric light source 35, located on one side of the doorway, FIG. 5, is powered across the and power lines. The light beam 36 emitted therefrom is directed across the doorway and impinges on photocell 37, mounted on the side of the doorway opposite the light source, so that a load entering or leaving the elevator car causes the light beam to be broken. The photocell 37 is connected to a photoelectric amplifier which derives its operating power from the and power lines. The photoelectric amplifier contains an output relay EE which becomes energized only when the photocell is dark.

The circuit is connected to operate in either the A or B mode according to the corresponding A or B position of a two section mode switch SW1. The mode switch consists of a first section SWla, FIG. 6, ganged to a second section SWlb, FIG. 7, to cause both sections to be simultaneously positioned at either the A or B position labeled in the drawings.

If the doors open to within six inches of being fully open without the beam being bro-ken and the circuit is operating in the A mode, the doors will begin to close at normal speed instantly upon the pressing of any car call button 44. Pressing a car call button picks up relay DS through the third contact on the button, FIG. 6. DS-l opens to drop-out DT. DT-Z closes to pick up TDA and energize TDAT, FIG. 7, through the A position of switch SWlb, DCL-5, and HC-2. TDA seals in, and power is sustained on TDAT, through TDA-3 and TDAT1. TDAT is energized, but is delayed in picking up. TDA-1 opens to drop-out DO. DO5 opens to remove power from the latch timer TD. TD opens its normally-open contact TD1. DO-3 opens to drop-out DE and signal the door operator to close the doors according to the previously described sequence of operation. If the circuit was operating in the B mode, TDAT would not have been energized, due to an open circuit at SWlb.

If the doors open fully in the A mode without the beam being'broken, or open fully due to operation in the B mode, or due to a hall call, the doors will instantly begin to close at normal speed upon reaching the fully open position. Upon the earliest interruption of the light beam, the doors will begin and continue to close at slow speed as long as the beam remains broken.

The interruption of the light beam after the doors have fully opened will cause relay EE, FIG. 5, to pick up and remain picked up as long as the beam is interrupted. OPEN LIMIT will have opened to drop-out DOL, opening DOL-1 to drop-out DO. DO-l opens to drop-out DT. DO3 opens to drop-out DE which signals the door operator to close the doors according to the following sequence of operation.

C-1 and C-Z close and C-4 opens. C-3 closes to connect resistor R-2 across the armature. EEX-1 closes to connect resistor R-4 across the armature through -3, 0-6, and EEZ-l. EEX-2 closes to pick up SDR through CLOSE LIMIT and 0-4. SDR-Z opens to insert resistor R-3 in series with the armature. Closing direction power is applied to the door motor through R1, C-l, armature, R-3 and C-2. Resistors R-2 and R4 are now c0nnected across the armature and resistor R-3 is connected in series with the armature so that a greater voltage drop appears across R-1, with a corresponding lower voltage across the armature than when the doors were to close at normal speed. The doors begin to close at slow speed. If the beam is not re-established during the door closing sequence, the doors will continue to their fully closed position at the slow speed.

If the beam is re-established while the doors are closing at slow speed, the doors will continue to close at slow speed for a short time interval, about two seconds, after the beam is re-established, after which time they will resume normal closing speed.

Re-establishment of the beam while the doors are closing at slow speed will cause relay EE to drop-out. EE-2 opens to remove power from delayed drop-out relay EEX, FIG. 6. After a short time interval, EEX drops-out. EEX-2 opens to drop-out SDR, FIG. 5 (provided the CLOSE SLOWDOWN position has not already been reached). SDR-1 opens without producing any elfect, because closed C-3 is in parallel with it. SDR-Z closes to short circuit resistor R-3, previously connected in series with the armature. EEX-1 opens to disconnect resistor R-4 from across the armature. A higher voltage is now developed across the armature and the doors resume their normal closing speed. Operation thereafter is the same as was previously described for a normal door closing cycle.

Should the beam be broken again, before the doors have fully closed, the doors will instantly reduce their closing speed to the slow speed upon the interruption of the beam. The subsequent interruption causes EE to pick up, closing EE-2 to pick up EEX. EEX-2 closes to pick up SDR. EEX-1 closes to connect R-4 in parallel with the armature through EEZ-l, 0-3, and 0-6. SDR-Z opens to insert R-3 in series with the armature. The applied armature voltage is reduced, and the doors attain slow closing speed as previously described.

The leading door edge is provided with a SAFETY EDGE contact which closes when the leading door edge strikes an obstruction. An OPEN button is provided in the car station for the purpose of re-opening and hold ing open the doors.

The doors are re-opened fully while closing at any speed if any one or more of the following devices is operated while the doors are closing: (1) the OPEN button is pressed, (2) the CAR CALL button corresponding to the floor at which the elevator has stopped is pressed, (3) the HALL CALL button corresponding to the set direction of travel for the car is pressed at the floor where the elevator has stopped, or (4) the SAFETY EDGE contact is actuated.

Pressing an appropriate CAR or HALL CALL button causes the CAR AND HALL CALL PICKUP contact to close momentarily, in turn causing relay UDC to close momentarily. The momentary closure of UDC-2 picks up relay DOX, FIG. 7, through DOL2, RA-4 and DCL3. The momentary closure of the SAFETY EDGE contact, or the OPEN button, picks up relay DOX through RA-4 and DCL3. DOX seals in through DCL-3, RA-4, DOX-2 and DOL-2. DOX-1 closes to pick up DO through RA-l and/or LRA-l. DO-3 closes to pick up DE through LRA2. Since the picking up of relay DE signals the door operator to open the doors, the doors open fully because DOX cannot drop-out until the OPEN LIMIT opens to drop DOL to open DOL 2 to drop DOX to open DOX-1 to drop D0 to open DO-3 to drop-out relay DE.

Upon reaching the fully open position, the doors immediately start to close if no device is being operated which is responsible to keep the doors open. The OPEN LIMIT switch opens to drop-out O and DOL, the door open circuit. The doors stop opening when 0 drops-out. DOL-2 opens to drop-out DOX, FIG. 6. DOX-1 and DOL-1 open to drop-out DO. DO-3 opens to drop-out DE. DE-l closes to pick up C, the door close circuit, which causes the doors to immediately start closing, as previously described.

The doors will remain fully open indefinitely as long as the OPEN button is pressed, the SAFETY EDGE contact is actuated, or the STOP switch is operated to its STOP position. Continuous pressure on the OPEN button or SAFETY EDGE contact causes relay DOX to pick up and remain picked up through RA-4 and DOL-3. DOX-1 closes to pick up DO through RA-l and/or LRA-l. DO3 closes to pick up DE through LRA-2. Operation of the STOP switch to its STOP position dropsout SAF. SAP-2 closes to pick up DE through RA2, DCL1, and/or LRA-3. As long as relay DE remains picked up, the door remains fully open.

A momentary operation of the STOP switch, FIG. 6, while the doors are closing will cause the doors to reverse and re-open only as long as the STOP switch is deactuated. The doors need not open fully should the STOP switch be returned to its actuated position before the doors have reached the fully open position. When the STOP switch is again actuated, the doors will reverse again and start closing.

A momentary operation of the STOP switch any time while the doors are opening as the car levels into a fioor does not prevent a momentary interruption of the beam from causing the doors to start immediately closing as soon as the beam is re-established. A momentary operation of the STOP switch when the doors have been fully closed for a short time (sufiicient for delayed drop-out relay TDCL to drop-out after de-energization) with the car at rest at a landing will not cause the doors to open to their fully open position if the beam is broken before the doors fully open, for although DT is picked up by delayed TDCL1, the breaking of the beam opens EE-l which drops-out DT, causing DT-Z to close which picks up TDA which opens TDA-1 to drop-out D0 which opens DO-3 to let DE drop-out.

The sequence of operation when the car is answering a hall call will now be given. Hall call relay HC, FIG. 7, is energized at this time, closing contact HC-l in the OX relay energizing circuit in FIG. 5, and opening contact HC-2 in the TDA and TDAT energizing circuit in FIG. 7.

With contact HC-2 now open, relay TDA can be energized only through the closing of the normally open latch timer contact TD, which is functional only in the event of a mechanical interlock failure. Since relay TDA cannot now pick up when the photobeam is broken during the door opening cycle, contact TDA-1, FIG. 6, cannot open to drop-out relay DO. Relay DO remains picked up until the doors become fully open and contact DOL-1 opens. Thus, the doors must always fully open.

With contact HC-l now closed, relay OX always becomes energized during the door opening movement while the doors are positioned between the EARLY OPEN SLOWDOWN and OPEN LIMIT switches, by the circuit through EARLY OPEN SLOWDOWN, OX relay coil, -5, and HC-l to Contact OX1 closes to connect resistors R4 and R-S across the door motor armature so that the doors always open at creep speed during the last six inches of opening movement.

The control operation is modified when an abnormal condition, such as a burned-out lamp, smoke, or dirt, prevents the photocell 37 from receiving the light beam. It will be assumed that the elevator is stopped at a landing. First relay EE, FIG. 5, drops-out, the same as when an obstruction is in the path of the beam. Contact =EE-2 closes to pick up relay EEX, FIG. 6. Contact EE-3 closes with no immediate effect. The doors close at the slow closing speed and, if further demands for service are registered by either a hall or car call, the elevator car will travel to another floor. As the elevator brake is energized and the car starts moving through the hoistway, the brake con-tact closes to pick up relay RA. RA3 closes to pick up EEY through EE-3 and DCL2. EEY seals in through EEY-1 and DOL-2. EEY-2 closes to pick up DOX through TDA-2 and DOL-2. EEY-3 closes to pick up EEZ. As the elevator initiates its slowdown for the next stopping floor, relay S drops-out. S-1 closes to seal in EEZ through EEZ-2 and EE-4.

As the car levels into the next stopping floor, the doors open at normal opening speed as the car enters the door operating zone, slowing down during the last six inches if the car is answering a hall call as previously described. While the doors are opening, the car is completing its leveling operation and the brake contact has not yet opened to cause relay RA to drop-out. Relay LRA, however, is picked up because the car levelling units, set for the door operating zone, have closed their contacts.

The doors now open to their fully open position as follows. Relay DO, FIG. 6, is sealed in through TDA-1, DOL-1 and DO-Z, while also being energized through LRA-l and DOX1. DE picks up through LRA-2 and DO-3 to signal the door operator to open the doors. As the doors leave their fully closed position, CLOSE LIMIT closes to pick up DCL and TDCL. TDCL-l opens to drop-out DT. If the car is not stopping for a hall call and if switch SWlb is thrown to its A position, DCL-S closes to pick up TDA and energize TDAT, both through DT-2, HC-2 and SWlb. TDA seals in and power is sustained on TDAT through TDA-3 and TDAT-1. TDA-2 opens but has no effect since DCL-3 is now closed. DOX remains picked up through DCL3, EEY-2 and DOL-2. DO remains picked up through LRA-1 and DOX-1. DE remains picked up through LRA-2 and DO-3. Until either the OPEN LIMIT opens or contact DE2 opens, relay 0 remains picked up and applies opening direction power to the door motor 61. Since DE-2 remains closed, the doors must open to their fully open position.

Upon becoming fully open, OPEN LIMIT opens to drop-out O and DOL. The doors stop under dynamic braking at their fully open position and immediately thereafter reclose at the medium closing speed, with no pause at the fully open position.

More particularly, when DOL drops-out, FIG. 5, DOL-2 opens to cause EEY and DOX to drop-out. EEX is still picked up through EE-Z because the photocell 37 is dark. EEZ is sealed in through EEZ-2, EE-4 and RA-5. DOX-1 opens to drop-out DO. DO-3 opens to drop-out DE. DE-l closes to pick up C through CLOSE LIMIT. EEX-2 closes to pick up SDR. EEX-1 closes, but since EEZ-1 is open, resistor R-4 is disconnected from across the armature. SDR-2 opens to insert R-3 in series with the armature. SDR-1 and C-3 close to connect R-Z in parallel with the armature. C-4- opens to remove the dynamic braking short circuit through 0-3 from across the armature. C-1 and C-2 close to apply 14 closing direction power to the door motor through R-l, C-1, armature, R-3 and C-2.

Because resistor R-4, FIG. 5, is not now connected across the armature, a smaller current is drawn through R1 than when the doors closed at slow speed. The corresponding voltage drop across R-1 is less and the voltage across the armature is more than that available for the slow door closing speed. The voltage across the armature is not as great as for normal closing speed because resistor R-3 is now connected in series with the armature, whereas at normal closing speed R-3 is shorted by contact SDR2. Therefore, the doors close at a medium closing speed between slow closing speed and normal closing speed.

When the failure which darkened the photocell is corrected, relay EE drops-out, opening EEr-4 to drop-out EEZ, FIG. 7. If the car has stopped at a floor, relay EEY will have dropped out when the doors became fully open, due to the opening of contact DOL-2. Since EEZ cannot pick up again, until EEY-3 closes, which cannot occur until relay EEY again picks up when the car is travelling through the hoistway with the doors fully closed and with the beam broken, contact EEZ1 remains closed to connect resistor R-4 across the armature any time thereafter the beam is interrupted. Therefore, normal operation is automatically restored whenever the failure is corrected while the car is stopped at a landing.

Should the PEG failure be corrected while the car is travelling through the hoistway, as could happen if smoke was responsible for the failure, the restored beam will cause relay EE to drop-out. EEY, FIG. 7, will have been picked up through RA-3, EE-3, and DCL-2, and sealed in through EEY-1 and DOL-2, before the fault was corrected. EEY-3 will be closed to keep EEZ picked up. Although contacts EE-S and EE-4 open when the beam is restored, EEY and EEZ remain picked up. When the car next stops at a floor, normal operation is restored at the instant when the doors become fully open, because the OPEN LIMIT opens to drop-out DOL, which causes DOL-2 to open Which causes EEY to drop-out, which opens contact EEY-3 to cause relay EEZ to drop-out. When relay EEZ drops-out, contact EEZ-1 closes to connect resistor R4 across the armature through 0-6, EEX-1 and O3 whenever the beam is subsequently interrupted, thus restoring normal operation.

The control operation is also modified when a door interlock mechanical failure prevents the hoistway door from being unlatched. As previously described, relay DO, FIG. 6 is picked up through UDC-l and sealed in through TDA-1, DOL-1 and DO2, when the elevator is conditioned to stop at the next floor for which a call is registered. As the car levels into the door operating zone, the CAR LEVELING UNIT switches, FIG. 6, close to pick up LRA. LRA-Z closes to pick up DE through DO-3. DE-Z closes to pick up 0 and cause opening power to be applied to the door motor.

Should the mechanical door interlock fail to unlatch the hoistway door, opening direction power will be applied to the doors, but they will not be able to overcome the mechanically locked condition. Under such a circumstance, override circuit 68 removes the opening power and applies closing power so that the door may fully reclose to re-establish the electrical interlock contacts 32, allowing the elevator car to continue to service other floors.

More particularly, as the car stops, the BRAKE contact opens to drop-out RA, FIG. 6. RA 6 closes to apply initiating power to latch timer TD through DCL-4 and DO-S. Upon the expiration of the latch timer interval, timer contact TD1, FIG. 7, closes to pick up TDA and energize slow pick up relay TDAT. TDA seals in and TDAT remains energized through TDA-3 and TDAT-1.

Assuming that other conditions are normal (the beam is operative and devices are not operated which could effect the picking up of relay DOX), contact TDA-1 opens to drop-out DO, FIG. 6. DO-3 opens to drop-out DE. DE-2 opens to drop-out O and remove opening direction power from the door motor. DE1 closes to pick up C, applying closing direction power to the door motor until the CLOSE LIMIT opens, which drops-out C to remove closing power. This operation allows the door interlock contacts 32 to be re-established, and the elevator may now proceed to travel to its next call.

Under conditions where relay DOX, FIG. 7, also would have been picked up when the doors could not open due to a mechanical failure to unlatch the hoistway doors, the same effect is produced by the following sequence of operations. Contact TDA-1 opens, but relay DO remains picked up through the parallel combination of RA-l and LRA-l in series with DOX-1. TDA-Z opens to drop-out DOX because DCL-3 is open. DOX-1 opens to drop-out DO. At this point, the sequence of operations is exactly the same as previously described above.

It will be apparent that the control is usable with a bank of elevator cars or with a single car. Similarly, changes can be made in other portions of the elevator control without afiecting the functioning of the door control.

While an illustrative embodiment of the invention is shown in the drawings and will be described in detail herein, the invention is susceptible of embodiment in many different forms and it should be understood that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated.

We claim:

1. In an elevator system having an elevator car with a doorway and a door for opening and closing said doorway, motive means for opening and closing said door, means for mechanically latching said door to prevent opening thereof by said motive means, means for unlatching the mechanical latch when the door is to open, and electrical interlock contacts established when said door is closed to allow movement of the car through a hoistway, door failure correction apparatus, comprising: means operative when said motive means is to open said door for generating a signal when said unlatching means fails to unlatch the mechanically latched door; and means responsive to said signal for terminating the door opening operation of said motive means and initiating the door closing operaton of said motive means to re-establish the electrical interlock contacts.

2. The door apparatus of claim 1 wherein said generating means includes a delay timer for generating said failure signal upon the expiration of a time period sufiicient for the door to have passed a given point across the passageway when the door has not passed said given point.

3. The door apparatus of claim 2, including close limit switch means positioned to be actuated only when said door is at its fully closed position, said fully closed position corresponding to said given point, said motive means including open door switching means actuated when said door is to open, and said generating means including said delay timer in series with said closed limit switch means and said door open switch means.

4. The door apparatus of claim 3 wherein said generating means includes elevator car movement means which become de-actuated when the elevator car moves through a hoistway, said elevator car movement means being connected in series with said delay timer, close limit switch means, and door open switch means for resetting said timer to its de-actuated condition subsequent to the generation of said failure indicating signal.

5. The door apparatus of claim 2 for an elevator system including a source of energy for projecting an energy field along said doorway and sensing means responsive to a change in condition of said energy field for generating a passenger transfer signal which modifies the opening and closing operation'of said motive means, including means responsive to the presence of the transfer signal from said sensing means prior to the initiation of the opening operation by said motive means for generating an error signal to indicate that said sensing means is inoperative, and means connected to said motive means and responsive to said error signal for enabling said motive means to initiate its opening operation when the door is to open regardless of the presence of said transfer signal.

References Cited UNITED STATES PATENTS 2,918,988 12/1959 Green l87--61 3,029,900 4/ 1962 Baker 187-61 3,200,905 8/1965 Holdridge 187-61 RICHARD E. AEGERTER, Primary Examiner.

HARVEY C. HORNSBY, Assistant Examiner.

US. Cl. X.R. 18752. 

